Deflector array, exposure apparatus, and device manufacturing method

ABSTRACT

A deflector array includes a plurality of deflectors, which deflect charged particle beams, arrayed on a substrate. Each of the plurality of deflectors includes a single opening formed in the substrate, and each of the plurality of deflectors includes a pair of electrodes that oppose each other through the opening and are configured to deflect a single charged particle beam. The plurality of deflectors are arrayed such that a length of the pair of electrodes in a longitudinal direction thereof is not less than a distance between centers of two of the plurality of deflectors that are located nearest to each other. The plurality of deflectors is arrayed to form a checkerboard lattice, and two openings of the two of the plurality of deflectors overlap in the longitudinal direction.

This application is a continuation application of copending U.S. patentapplication Ser. No. 11/779,498, filed on Jul. 18, 2007.

This application claims the benefit of Japanese Patent Application No.2006-197747, filed Jul. 20, 2006, which is hereby incorporated byreference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to, e.g., a deflector array suitable as acomponent of a charged particle beam exposure apparatus, such as anelectron beam exposure apparatus and an ion beam exposure apparatus,used to manufacture a device, such as a semiconductor integrated device,an exposure apparatus having the deflector array, and a devicemanufacturing method using the exposure apparatus.

2. Description of the Related Art

Conventionally, as shown in FIG. 10, a deflector 200 is used as acomponent of a charged particle beam exposure apparatus, such as anelectron beam exposure apparatus and an ion beam exposure apparatus,used to manufacture a device, such as a semiconductor integrated device.As shown in FIG. 10, the deflector 200 has a substrate 211, an opening212 formed to pass a charged particle beam to the substrate 211, and apair of electrodes 213 opposing each other through the opening 212.

As shown in FIG. 11, the deflectors 200 are arrayed such that adirection 221 of a line connecting the centers of two deflectors 200located nearest to each other become perpendicular to a direction 300 inwhich a pair of opposing electrodes 213 deflect a charged particle beam.

For this reason, a length L of the electrode 213 of the deflector 200cannot be longer than a distance D between the centers of two deflectorslocated nearest to each other in the direction 221.

The deflector 200 of the deflector array used for a charged particlebeam exposure apparatus for drawing a pattern with a plurality ofcharged particle beams must be arranged at the pitch of the chargedparticle beams, e.g., a pitch of several tens to several hundreds ofmicrons. This makes it impossible to sufficiently ensure the length ofthe electrode 213 of the deflector 200 to result in an increase indeflection aberration.

When, however, the charged particle beam exposure apparatus uses acharged particle beam deflected by the deflector 200 of the deflectorarray, deflection aberration must be decreased to attain high drawingaccuracy. To decrease the deflection aberration of the deflector 200 ofthe deflector array, it is effective to maximize the length of theopposing electrodes 213.

Japanese Patent Laid-Open No. 7-297107 discloses deflectors arrayed tomake uniform the signal delay amount.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a deflector arrayhaving an arrangement advantageous to decrease deflection aberration,and an application example of the deflector array.

A first aspect of the present invention relates to a deflector array inwhich a plurality of deflectors, which deflect charged particle beams,are arrayed on a substrate. In the array, each deflector includes anopening formed on the substrate, and a pair of electrodes opposing eachother through the opening. The length of the pair of electrodes in thelongitudinal direction is not less than the distance between the centersof two deflectors, which are located nearest to each other.

According to a preferred embodiment of the present invention, thedirection of a line connecting the centers of two deflectors, which arelocated nearest to each other, form an angle of 45° with respect to thedirection in which the deflector deflects the charged particle beam.Alternatively, according to another preferred embodiment of the presentinvention, the direction of a line connecting the centers of twodeflectors, which are located nearest to each other, form an angle of63.4° with respect to the direction in which the deflector deflects thecharged particle beam.

According to a preferred embodiment of the present invention, thedirection in which the deflector deflects the charged particle beam isperpendicular to the longitudinal direction of the pair of electrodes.

According to a preferred embodiment of the present invention, the pairof electrodes are parallel to each other. Alternatively, according toanother preferred embodiment of the present invention, the distancebetween the pair of electrodes shortens toward the end portions of thepair of electrodes.

A second aspect of the present invention relates to an exposureapparatus which exposes a wafer with a charged particle beam. Theexposure apparatus includes a charged particle source, which emits thecharged particle beam, a first electron optical system which forms aplurality of intermediate images of the charged particle source, asecond electron optical system which projects the plurality ofintermediate images formed by the first electron optical system onto thewafer, and a positioning apparatus which holds, drives, and positionsthe wafer. The first electron optical system includes theabove-described deflector array.

A third aspect of the present invention relates to a devicemanufacturing method. The manufacturing method includes the steps ofexposing a wafer using the above-described exposure apparatus, anddeveloping the wafer.

According to the present invention, a deflector array having anarrangement advantageous to decrease deflection aberration, and anapplication example of the deflector array are provided.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments, with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing a deflector array according to the firstembodiment of the present invention;

FIG. 2 is a plan view showing a deflector array according to the secondembodiment of the present invention;

FIG. 3 is a plan view showing a deflector array according to the thirdembodiment of the present invention;

FIGS. 4A and 4B are views schematically showing the main part of anelectron beam exposure apparatus according to a preferred embodiment ofthe present invention;

FIG. 5 is a view for explaining electron optical systems for each columnof the electron beam exposure apparatus according to the preferredembodiment of the present invention;

FIG. 6 is a view for explaining the function of a multi-source module ofthe electron beam exposure apparatus according to the preferredembodiment of the present invention;

FIG. 7 is a block diagram for explaining a system configuration of theelectron beam exposure apparatus according to the preferred embodimentof the present invention shown in FIGS. 4A and 4B;

FIG. 8 is a flowchart for explaining the device manufacture using anexposure apparatus according to the present invention;

FIG. 9 is a flowchart illustrating details of the wafer process in step4 of the flowchart shown in FIG. 8;

FIG. 10 is sectional view showing a deflector of a deflector arrayaccording to the prior art; and

FIG. 11 is a plan view showing the deflector array according to theprior art.

DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present invention will be described below withreference to the accompanying drawings.

[First Embodiment]

A deflector array according to the first embodiment of the presentinvention will be explained with reference to the plan view shown inFIG. 1. The deflector array is formed by arraying a plurality ofdeflectors 200 a and 200 j for deflecting charged particle beams on asubstrate 211. Each deflector has an opening 212 a formed on thesubstrate 211, and a pair of electrodes 213 a opposing each otherthrough the opening 212 a.

A length L of the pair of electrodes 213 a in the longitudinal directionis not less than a distance D between the centers of the two deflectors200 a and 200 j located nearest to each other. In the deflector arrayaccording to the first embodiment, therefore, the length L of the pairof electrodes 213 a in the longitudinal direction can be relativelylong. This makes it possible to decrease the deflection aberration ofcharged particle beams deflected by the deflectors 200 a and 200 j.

In the first embodiment, a direction 300 in which a deflector deflects acharged particle beam is perpendicular to the longitudinal direction ofthe electrode 213 a.

Also, in the first embodiment, the distance between each pair ofelectrodes 213 a shortens toward their end portions.

Applying the deflector array according to the first embodiment to anelectron beam exposure apparatus makes it possible to attain highdrawing accuracy.

[Second Embodiment]

A deflector array according to the second embodiment of the presentinvention will be explained with reference to the plan view shown inFIG. 2. Directions 246 and 247 form an angle of about 45° with respectto a direction 300 in which a deflector deflects a charged particlebeam. The directions 246 and 247 are of lines connecting the center of adeflector 200 b to the centers of deflectors 200 d and 200 e and to thecenters of deflectors 200 c and 200 f, respectively, all of which arelocated nearest to the deflector 200 b.

In the deflector array according to the second embodiment, a length L ofelectrodes 213 a of the deflectors 200 b, 200 c, 200 d, 200 e, and 200 fcan be about √{square root over (2)} times as long as a distance Dbetween the center of the deflector 200 b and the centers of thedeflectors 200 c, 200 d, 200 e, and 200 f, all of which are locatednearest to the deflector 200 b.

According to the second embodiment, it is possible to obtain a deflectorarray, which minimizes deflection aberration. In addition, applying thedeflector array according to the second embodiment to an electron beamexposure apparatus makes it possible to attain high drawing accuracy.

[Third Embodiment]

A deflector array according to the third embodiment of the presentinvention will be explained with reference to the plan view shown inFIG. 3. One of directions 291 and 292 forms an angle of about 63.4° withrespect to a direction 300 in which a deflector deflects a chargedparticle beam. The directions 291 and 292 are of lines connecting thecenter of deflector 200 g to the centers of deflectors 200 h locatednearest to it.

In the deflector array according to the third embodiment, a length L ofelectrodes 213 b of the deflectors 200 g and 200 h can be about √{squareroot over (5)} times as long as a distance D between the center of thedeflector 200 g and the centers of the deflectors 200 h located nearestto it.

According to the third embodiment, it is possible to obtain a deflectorarray which minimizes deflection aberration. In addition, applying thedeflector array according to the third embodiment to an electron beamexposure apparatus makes it possible to attain high drawing accuracy.

An electron beam exposure apparatus (drawing apparatus) using adeflector array, according to an embodiment of the present invention,will be explained.

The following description will exemplify an exposure apparatus whichadopts an electron beam as the charged particle beam. However, thepresent invention is also applicable to an exposure apparatus using acharged particle beam of another type, such as an ion beam.

An electron beam exposure apparatus using a deflector array according tothe present invention will be explained with reference to the schematicviews of the main part shown in FIGS. 4A and 4B.

A multi-source module 1 forms a plurality of electron source images byemitting electron beams from its electron source (charge particlesource). In this example, 3×3 multi-source modules 1 are arrayed, anddetails thereof will be described later.

In this example, each of magnetic field lens arrays 21, 22, 23, and 24forms an electron optical system and has magnetic disks MD. The magneticdisks MD have 3×3 openings with the same shape, and are verticallyarranged with spacings between them. A common coil CC excites themagnetic disks MD. As a consequence, each opening serves as a magneticpole of a magnetic field lens ML to generate a lens magnetic field asdesigned.

Four magnetic field lenses ML1, ML2, ML3, and ML4 corresponding to themagnetic field lens arrays 21, 22, 23, and 24 project the plurality ofelectron source images of each multi-source module 1 onto a wafer 4.

An optical system, which acts on electron beams from one multi-sourcemodule 1 until they strike the wafer, is defined as a column. That is,in this example, the exposure apparatus includes nine columns, column 1to column 9.

The two corresponding magnetic field lenses of the magnetic field lensarrays 21 and 22 once form an image. Then, the two correspondingmagnetic field lenses of the magnetic field lens arrays 23 and 24project the resultant image onto the wafer 4.

The common coils individually control the respective excitationconditions of the magnetic field lens arrays 21, 22, 23, and 24. Thismakes it possible to adjust the optical characteristics (focal position,image rotation, and magnification) of each column uniformly, i.e., bythe same amount.

A main deflector 3 is a positioning apparatus for deflecting a pluralityof electron beams from the multi-source module 1 and displacing aplurality of electron source images in the X and Y directions on thewafer 4. A stage 5 is a positioning apparatus which supports the wafer 4to be movable in the X and Y directions perpendicular to an optical axisAX (Z-axis) and the rotation direction about the Z-axis. A stagereference plate 6 is fixed on the stage 5. A reflected electron detector7 detects electrons reflected when an electron beam strikes a mark onthe stage reference plate 6.

FIG. 5 is a view showing details of one column. The multi-source module1 and its function of adjusting the optical characteristics of anelectron beam applied from the multi-source module 1 to the held wafer 4will be explained.

An electron source 101 (charged particle source) formed by an electrongun emits an electron beam to form a crossover image. A condenser lens102, which forms an electron optical system, collimates the electronbeam emitted by the electron source 101 into a collimated electron beam101 a.

The condenser lens 102 in this example is an electro-static lensincluding three opening electrodes. An aperture array 103 is an electronoptical system having a plurality of two-dimensionally arrangedopenings. A lens array 104 is an electron optical system having aplurality of two-dimensionally arrayed electro-static lenses. Theplurality of electro-static lenses have the same optical power.

Deflector arrays 105 and 106 are electron optical systems, each of whichis formed by two-dimensionally arraying electro-static deflectors thatcan be driven individually.

A blanker array 107 is an electron optical system formed bytwo-dimensionally arrayed electro-static blankers that can be drivenindividually.

A deflector array represented by those according to the above-describedfirst to third embodiments is suitable as the deflector arrays 105 and106 and blanker array 107.

The functions of units of the exposure apparatus will be explained withreference to FIG. 6. The aperture array 103 divides a collimatedelectron beam from the condenser lens 102 into a plurality of electronbeams.

Each divided electron beam forms an intermediate image of the electronsource (charged particle source) on a corresponding blanker of theblanker array 107 via a corresponding electro-static lens of the lensarray 104. At this time, the deflector arrays 105 and 106 individuallyadjust the positions (positions within a plane perpendicular to theoptical axis) of the intermediate images of the electron source formedon the blanker array 107.

An electron beam deflected by the blanker array 107 is shielded by ablanking aperture AP shown in FIG. 5 and, therefore, does not reach thewafer 4. On the other hand, an electron beam, which is not deflected bythe blanker array 107, is not shielded by the blanking aperture AP shownin FIG. 5 and, therefore, reaches the wafer 4.

Referring back to FIG. 6, each of a plurality of intermediate images 101b of the electron source (charged particle source) formed by themulti-source module 1 is projected onto the wafer 4 via the twocorresponding magnetic field lenses of the magnetic field lens arrays 21and 22.

Of the optical characteristics, when the plurality of intermediateimages are projected onto the wafer 4, the image rotation andmagnification can be adjusted by the deflector arrays 105 and 106capable of adjusting the position of each intermediate image on theblanker array 107. The focal position can be adjusted by dynamic focuslenses (electro-static or magnetic field lenses) 108 and 109 arrangedfor each column.

A system configuration of the exposure apparatus will be explained withreference to the system configuration shown in FIG. 7. A blanker arraycontrol circuit 41 individually controls the plurality of blankers ofthe blanker array 107. A deflector array control circuit 42 individuallycontrols the deflectors of the deflection arrays 104 and 105.

A D_FOCUS control circuit 43 individually controls the dynamic focuslenses 108 and 109. A main deflector control circuit 44 controls themain deflector 3. A reflected electron detection circuit 45 processes asignal from the reflected electron detector 7. The blanker array controlcircuit 41, deflector array control unit 42, D_FOCUS control circuit 43,main deflector control circuit 44, and reflected electron detectioncircuit 45 are prepared for each of the columns, column 1 to column 9.

A magnetic field lens array control circuit 46 controls the common coilsof the magnetic field lens arrays 21, 22, 23, and 24. A stage drivingcontrol circuit 47 controls the driving of the stage 5 in cooperationwith a laser interferometer (not shown) for detecting its position. Amain control system 48 controls the above-described plurality of controlcircuits to manage the overall electron beam exposure apparatus.

An embodiment of a device manufacturing method using the above-describedexposure apparatus will be explained with reference to FIGS. 8 and 9.

FIG. 8 is a flowchart for explaining the manufacture of a device (e.g.,a semiconductor chip, such as an IC or LSI, an LCD, or a CCD). Asemiconductor chip manufacturing method will be exemplified here. Instep 1 (circuit design), the circuit of a semiconductor device isdesigned. In step 2 (exposure control data preparation), exposurecontrol data is prepared on the basis of the designed circuit pattern.In step 3 (wafer manufacture), a wafer is manufactured using a materialsuch as silicon. In step 4 (wafer process), called a pre-process,circuit patterns are formed on the wafer by using the above-describedexposure apparatus. The exposure apparatus is controlled by the exposurecontrol data. In step 5 (assembly), called a post-process, asemiconductor chip is formed using the wafer manufactured in step 4.This step includes an assembly step (dicing and bonding) and a packagingstep (chip encapsulation).

In step 6 (inspection), the semiconductor device manufactured in step 5undergoes inspections, such as an operation confirmation test and adurability test. After these steps, the semiconductor device iscompleted and shipped, in step 7.

FIG. 9 is a flowchart showing details of the wafer process in step 4. Instep 11 (oxidation), the wafer surface is oxidized. In step 12 (CVD), aninsulating film is formed on the wafer surface. In step 13 (electrodeformation), an electrode is formed on the wafer by vapor deposition.

In step 14 (ion implantation), ions are implanted in the wafer. In step15 (resist process), a photosensitive agent is applied to the wafer. Instep 16 (exposure), the exposure apparatus draws the circuit pattern onthe wafer in accordance with the exposure control data. In step 17(development), the exposed wafer is developed. In step 18 (etching),portions other than the developed resist image are etched. In step 19(resist removal), any unnecessary resist remaining after etching isremoved. These steps are repeated to form multiple circuit patterns onthe wafer.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

1. A deflector array comprising: a plurality of deflectors, whichdeflect charged particle beams, arrayed on a substrate, wherein each ofsaid plurality of deflectors includes a single opening formed in thesubstrate, and each of said plurality of deflectors including a pair ofelectrodes that oppose each other through the opening and beingconfigured to deflect a single charged particle beam, and wherein saidplurality of deflectors are arrayed such that a length of said pair ofelectrodes in a longitudinal direction thereof is not less than adistance between centers of two of said plurality of deflectors that arelocated nearest to each other, said plurality of deflectors beingarrayed to form a checkerboard lattice, and two openings of the two ofsaid plurality of deflectors overlapping in the longitudinal direction.2. The deflector array according to claim 1, wherein said pair ofelectrodes are formed such that a distance between said pair ofelectrodes shortens from centers toward end portions of said pair ofelectrodes.
 3. An exposure apparatus which exposes a wafer with acharged particle beam, the apparatus comprising: a charged particlesource which emits the charged particle beam; a first electron opticalsystem which forms a plurality of intermediate images of said chargedparticle source; a second electron optical system which projects theplurality of intermediate images formed by said first electron opticalsystem onto the wafer; and a positioning apparatus which holds andpositions the wafer, wherein said first electron optical system includesa deflector array defined in claim
 1. 4. A method of manufacturing adevice, the method comprising: exposing a wafer with a charged particlebeam using an exposure apparatus defined in claim 3; developing theexposed wafer; and processing the developed wafer to manufacture thedevice.
 5. The deflector array according to claim 1, wherein thedeflector array includes deflectors with three rows and three columns.